Notice Number: (NOT-OD-09-058) Notice Title: NIH Announces the Availability of Recovery Act Funds for Competitive Revision Applications Project Summary The long term goal of this project is to develop a radically new Computed Tomography (CT) system design that promises to provide superior dose-efficiency and decreased patient dose, improved spatial and temporal resolution, and artifact-free wide volume coverage in a single fast rotation. The underlying concept, Inverse Geometry CT (IGCT), employs an array of x-ray sources in contrast to the single x-ray source used by conventional CT systems. The approach promises volumetric coverage in a single fast scan without "cone beam artifacts" that alternative techniques face. In addition, for comparable image quality, the approach could lead to significant reductions in patient dose. The main goal of the parent R01 grant is to develop the first ever, gantry-based IGCT system. Because of resource limitations, the current plan is for this first implementation to have one source module comprised of 8 sources. The aim of this competitive revision application is to build 3 additional source modules, bringing the total to 32 sources. The revision will fund the materials and labor for construction and integration of the additional sources into a housing that was already designed to accommodate 4 modules. The detailed evaluation and testing of the improved source array will be conducted using resources from the parent grant. This scope enhancement will allow us to study the virtual bowtie and to test the performance of IGCT under conditions closer to those of eventual clinical settings. PUBLIC HEALTH RELEVANCE: Inverse Geometry CT is capable of organ-in-rotation imaging without cone-beam artifacts, has the potential for improved spatial and temporal resolution, and offers an approach to significantly reduce the radiation exposure needed to obtain the required clinical information. Historically, improvements in CT performance have always led to important new applications, and minimizing the radiation dose of CT scanning is a significant benefit, especially in children and other groups at higher risk from the effects of ionizing radiation. This competitive revision will accelerate the development and evaluation of this promising technology.